/*
 * Copyright 2002-2007 Network Engine for Objects in Lund AB [neotechnology.com]
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.impl.traversal;

import org.neo4j.api.core.Node;
import org.neo4j.api.core.TraversalPosition;
import org.neo4j.api.core.Traverser;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Iterator;


/**
 * This class is used for traversers that has been sorted. A normal traverser 
 * will return a <CODE>SortedTraverser</CODE> when the <CODE>sort</CODE> method 
 * is invoked. Since a sorting operation requires one to go throu all elements 
 * that should be sorted the <CODE>SortedTraverser</CODE> just encapsulates an 
 * iterator to the sorted list of nodes.
 */
class SortedTraverser implements Traverser
{
	private Iterator<Node> nodesIterator = null;
	
	/**
	 * Creates a sorted traverser from the sorted list of <CODE>nodes</CODE>
	 * 
	 * @param nodes the list of sorted nodes
	 */
	SortedTraverser( List<Node> nodes )
	{
		this.nodesIterator = nodes.iterator();
	}
	
	// javadoc: see java.util.Iterator
	public Object next()
	{
		return nextNode();
	}
	
	// javadoc: see java.util.Iterator
	public boolean hasNext()
	{
		return nodesIterator.hasNext();
	}
	
	// javadoc: see java.util.Iterator
	public void remove() { throw new UnsupportedOperationException(); }
	
	// javadoc: see Traverser
	public Node nextNode()
	{
		return (Node) nodesIterator.next();
	}
	
	// javadoc: see Traverser
	public Collection<Node> getAllNodes()
	{
		// Temp storage
		List<Node> tempList = new ArrayList<Node>();
		
		// Traverse until the end, my beautiful friend
		while ( this.hasNext() )
		{
			tempList.add( this.nextNode() );
		}
		
		// Return nodes
		return tempList;
	}
	
	// javadoc: see Traverser
	public Traverser sort( NodeSortInfo<Node> nsi )
	{
		ArrayList<Node> tempList = new ArrayList<Node>();
		
		// Traverse and get all remaining nodes
		while ( this.hasNext() )
		{
			tempList.add( this.nextNode() );
		}
		
		Collections.sort( tempList, nsi );
		return new SortedTraverser( tempList );
	}

	public TraversalPosition currentPosition()
	{
		// TODO Auto-generated method stub
		return null;
	}

	public Iterator<Node> iterator()
	{
		// TODO Auto-generated method stub
		return null;
	}
}
